Labour leader Ed Miliband was heckled and booed during an address to trade
unions today after repeating his condemnation of this summer’s strikes as a
“mistake”.

In a speech to the TUC congress in London, Mr Miliband said he was unmoved on his position not to back the strike action, which saw tens of thousands of teachers and civil servants protest over pensions.

He appeared the critical friend of the unions, saying: ""Of course, there are times when you and I will disagree. You will speak your mind. And so will I.

"The right to industrial action will be necessary, as a last resort," he said.

"But in truth, strikes are always the consequence of failure. Failure on all sides. Failure we cannot afford as a nation. Instead your real role is as partners in the new economy."

Mr Miliband said he understood why millions of public sector workers felt angry over the Government's pension reforms: "But while negotiations were going on, I do believe it was a mistake for strikes to happen. I continue to believe that.”

Some of the 300 delegates shouted "shame" and took issue with the Labour leader's message.

His speech comes as unions are gearing up for more industrial action in the coming months, which could involve huge numbers of public sector workers in the biggest outbreak of unrest for decades.

He said: “But what we need now is meaningful negotiation to prevent further confrontation over the autumn. Ministers need to show public sector workers - and the people who rely upon those services - that they are serious about finding a way forward."

He said: "Unions can offer businesses the prospect of better management, better relationships. As you did during the recession. Of course the right to industrial action will be necessary, as a last resort.

Unions currently provide more than 80 per cent of Labour's funding and Mr Miliband was elected party leader last year, narrowly beating his brother David, with a swing from the trade union vote.

But he is thought to be planning to reduce their voting power at Labour conferences.

Today’s address was thought to be a good indicator of his relationship with the trade union movement, but as the audience jeered, it appeared more fractured than ever.

He warned them that they risk “irrelevance”, saying that they must embrace change: “You know the biggest challenge you face when you try to do this: relevance.

“Relevance in how firms grow. Relevance in how workers get on. Relevance right across the private sector. And you know you will never have relevance for many workers in this country if you allow yourselves to be painted as the opponents of change,” he said.

“In the new economy you can, and must, be the agents of the right kind of change.

He also called on unions to do more to encourage workers in the private sector as well as the public, where they have the majority of their members.

"The challenge for unions is this: to recognise that Britain needs to raise its game if we are to meet the challenges of the future and to get private sector employers in the new economy to recognise that you are relevant to that future," he said.

"Just 15 per cent of the private sector workforce are members of trade unions. But unions can offer businesses the prospect of better management, better relationships - trust.

"Britain needs you to take your place as partners in the new economy."

Bob Crow, general secretary of the Rail Maritime and Transport union, said Mr Miliband "needed to decide just whose side he is on".

"Criticising teachers and other workers taking strike action to defend jobs, services and pensions alienates core labour supporters in their hundreds of thousands and is a political suicide mission," he said.

"You can't play political games when workers are facing the biggest all out attack on their rights and their livelihoods since the war. A Labour leader who doesn't stand by the workers is on a one way ticket to oblivion."